//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24503 SUBJECT: LIGO/Virgo S190512at: Identification of a GW compact binary merger candidate DATE: 19/05/12 19:05:01 GMT FROM: Deep Chatterjee at University of Wisconsin, Milwaukee The LIGO Scientific Collaboration and the Virgo Collaboration report: We identified the compact binary merger candidate S190512at during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-05-12 18:07:14.422 UTC (GPS time: 1241719652.422). The candidate was found by the PyCBC Live [1], CWB [2], GstLAL [3], MBTAOnline [4], and spiir [5] analysis pipelines. S190512at is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-09 Hz, or about one in 16 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S190512at The classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), BNS (<1%), NSBH (<1%), or MassGap (<1%). Assuming the candidate is astrophysical in origin, there is strong evidence against the lighter compact object having a mass < 3 solar masses (HasNS: <1%). Using the masses and spins inferred from the signal, there is strong evidence against matter outside the final compact object (HasRemnant: <1%). One skymap is available at this time and can be retrieved from the GraceDB event page: * bayestar.fits.gz, an updated localization generated by BAYESTAR [6], distributed via GCN notice about 53 minutes after the candidate. For the bayestar.fits.gz skymap, the 90% credible region is 399 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1331 +/- 341 Mpc (a posteriori mean +/- standard deviation). No Preliminary Notice was sent for this event due to a technical problem. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo Public Alerts User Guide . [1] Nitz et al. PRD 98, 024050 (2018) [2] Klimenko et al. PRD 93, 042004 (2016) [3] Messick et al. PRD 95, 042001 (2017) [4] Adams et al. CQG 33, 175012 (2016) [5] Qi Chu, PhD Thesis, The University of Western Australia (2017) [6] Singer & Price PRD 93, 024013 (2016) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24504 SUBJECT: LIGO/Virgo S190512at: IceCube Neutrino Search DATE: 19/05/12 19:08:15 GMT FROM: Claudio Kopper at IceCube/U of Alberta The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search for track-like muon neutrino events consistent with the sky localization of S190512at-2-Initial in a time range of 1000 seconds centered on the alert event time (2019-05-12 17:58:54.000 UTC to 2019-05-12 18:15:34.000 UTC) during which IceCube was collecting good quality data. No track-like events are found in spatial coincidence with the 90% spatial containment of S190512at calculated from the map circulated in the preliminary notice. IceCube's sensitivity to point sources within the location spanned by the 90% spatial containment of S190512at ranges from 0.029 to 0.568 GeV cm^-2 in a 1000 second time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24507 SUBJECT: LIGO-Virgo S190512at: AGILE MCAL observations DATE: 19/05/12 20:02:58 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini, G. Piano (INAF/IAPS), F. Lucarelli, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report on behalf of the AGILE Team: In response to the LIGO-Virgo GW event S190512at at T0 = 2019-05-12 18:07:14 (UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) data found no data acquisitions related to the event, due to a complete Earth occultation of the S190512at 90% c.l. localization region. The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24508 SUBJECT: LIGO/Virgo S190512at: INTEGRAL inactive at the time of the event DATE: 19/05/12 20:19:13 GMT FROM: James Rodi at IAPS-INAF Enrico Bozzo, Volodymyr Savchenko, Carlo Ferrigno (ISDC/UniGE, Switzerland) James Rodi, (IAPS-Roma, Italy) Sandro Mereghetti (INAF IASF-Milano, Italy) on behalf of the INTEGRAL multi-messenger collaboration: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration The INTEGRAL spacecraft has a highly elliptical orbit and the instruments are switched off around the perigee passage, every 2.6 days, to prevent radiation-induced damages. Unfortunately, at the time of the LIGO/Virgo trigger S190512at (2019-05-12 18:07:14.422 UTC) the spacecraft was preparing to start the observations after the perigee passage between the orbits number 2089 and 2090 and no scientific instrument data are available. INTEGRAL observations will restart at approximately 2019-05-13 03:08:07 UTC. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24513 SUBJECT: LIGO/Virgo S190512at: Fermi GBM Observations DATE: 19/05/13 01:19:59 GMT FROM: Suraj Poolakkil at UAH S. Poolakkil (UAH) and C.M. Hui (NASA/MSFC) report on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group: For S190512at, and using the updated BAYESTAR skymap, Fermi-GBM was observing 34.7% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo detection of GW trigger S190512at (GCN 24503). An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVC localization region is behind the Earth for Fermi, located at RA = 308.1 and Dec = -3.6 with a radius of 67.2 degrees. We therefore set upper limits on impulsive gamma-ray emission. Using the representative soft, normal, and hard GRB-like spectral templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by the remaining visible GW localization probability (in units of erg/s/cm^2): Timescale soft norm hard ----------------------------------------------- 0.128 s: 2.4e-07 4.3e-07 1.0e-06 1.024 s: 5.3e-08 1.1e-07 2.5e-07 8.192 s: 2.3e-08 2.3e-08 8.0e-08 Assuming the median luminosity distance of ~1331 Mpc from the GW detection, we estimate intrinsic luminosity upper limits of (0.8-7.9)E49 erg/s for the soft template, (0.7-12.7)E49 erg/s for the normal template, and (3.9-49.3)E49 erg/s for the hard template over the 1 keV-10 MeV energy range. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24514 SUBJECT: LIGO/Virgo S190512at: MAXI/GSC Observations DATE: 19/05/13 01:40:49 GMT FROM: Mutsumi Sugizaki at Tokyo Tech./MAXI S. Sugita, M. Serino (AGU), H. Negoro (Nihon U.), M. Sugizaki, N. Kawai (Tokyo Tech), M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), S. Nakahira, T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, H. Nishida, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), M. Shidatsu (Ehime U.), M. Oeda, K. Shiraishi (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after the LVC trigger S190512at at 2019-05-12 18:07:14.422 UTC (GCN 24503). At the trigger time of S190512at, the high-voltage of MAXI/GSC was on, but the FOV was out of the 90% credible region of the bayestar skymap. The first one-orbit (92 min) scan observation with GSC after the event covered 90% of the 90% credible region of the bayestar skymap from 18:33:5 to 19:38:1 UTC (T0+1551 to T0+5457 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24515 SUBJECT: LIGO/Virgo S190512at: Fermi-LAT search for a high-energy gamma-ray counterpart DATE: 19/05/13 10:01:22 GMT FROM: Magnus Axelsson at Stockholm U. M. Axelsson (KTH and Stockholm Univ.), D. Kocevski (NASA/MSFC) and F. Dirirsa (Univ. of Johannesburg) report on behalf of the Fermi-LAT collaboration: We have searched data collected by the Fermi Large Area Telescope (LAT) on May 12, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S190512at (GCN 24503). We define "instantaneous coverage" as the integral over the region of the LIGO probability map that is within the LAT field of view at a given a time, and "cumulative coverage" as the integral of the instantaneous coverage over time. At the time of the trigger (T0 = 2019-05-12 18:07:14.422 UTC), the entire LIGO probability region was either obscured by the Earth or outside the Fermi-LAT field of view. Coverage of the region started around T0 + 1000 s, and reached 100% cumulative coverage at approximately T0 + 7 ks. We performed a search for a transient counterpart within the observed region of the 90% contour of the LIGO map in a fixed time window from T0 + 1 ks to T0 + 10 ks. No significant new sources were found. We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky, and no additional excesses were found. Energy flux upper bounds for the fixed time interval between 100 MeV and 100 GeV for this search vary between 2.5e-10 and 3.5e-9 [erg/cm^2/s]. The Fermi-LAT point of contact for this event is Feraol Dirirsa (fdirirsa@uj.ac.za). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24516 SUBJECT: LIGO/Virgo S190512at: ANTARES neutrino search DATE: 19/05/13 10:16:14 GMT FROM: Damien Dornic at CPPM,France M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (APC/Universite Paris Diderot), M. Colomer (APC/Universite Paris Diderot)), D. Dornic (CPPM/CNRS), A. Kouchner (APC/Universite Paris Diderot), T. Pradier (IPHC/Universite de Strasbourg) report on behalf of the ANTARES Collaboration: Using on-line data from the ANTARES detector, we have performed a follow-up analysis of the recently reported LIGO/Virgo S190512at event using the 90% contour of the initial bayestar probability map provided by the GW interferometers (GCN#24503). The ANTARES visibility at the time of the alert, together with the 50% and 90% contours of the probability map are shown in https://www.cppm.in2p3.fr/~dornic/events_runo3/S190512at.png . Considering the location probability provided by the LIGO/Virgo collaborations, there is a 83% chance that the GW emitter was in the ANTARES **upgoing** field of view at the time of the alert. No up-going muon neutrino candidate events were recorded in the ANTARES sky during a +/- 500s time-window centered on the time (2019-05-12 18:07:14 UT) and in the 90% contour of the S190512at event. The expected number of atmospheric background events in the region visible by ANTARES is 1.6e-4 in the +/- 500s time window. An extended search during +/- 1 hour gives no up-going muon neutrino coincidence. The expected number of atmospheric background events in the region visible by ANTARES is 1.2e-3 in this larger time window. ANTARES is the largest undersea neutrino detector, installed in the Mediterranean Sea, and it is primarily sensitive to neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a competitive sensitivity to this position in the sky. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24518 SUBJECT: LIGO/Virgo S190512at: Swift/BAT Counterpart Search DATE: 19/05/13 15:22:16 GMT FROM: Amy Lien at GSFC T. Sakamoto (AGU), S. D. Barthelmy (NASA/GSFC), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), A. A. Breeveld (MSSL-UCL), A. P. Beardmore (U. Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), V. D'Elia(ASDC), S. Emery (UCL-MSSL), P. A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU), D. Hartmann (Clemson U.), J. A. Kennea (PSU), H. A. Krimm (NSF), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), B. Mingo (U. Leicester), J. A. Nousek (PSU), S. R. Oates (Uni. of Warwick), P. T. O'Brien (U. Leicester), J. P. Osborne (U. Leicester), C. Pagani (U. Leicester), K. L. Page (U.Leicester), M. Perri (ASDC), J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (PSU), E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team: We report the search results in the BAT data within T0 +/- 100 s of the LVC event S190512at (LIGO/VIRGO Collaboration GCN Circ. 24503), where T0 is the LVC trigger time (2019-05-12T18:07:14.422 UTC). The center of the BAT FOV at T0 is RA = 92.704 deg, DEC = -30.367 deg, ROLL = 302.899 deg. The BAT Field of View (>10% partial coding) covers 0.00% of the integrated LVC localization probability, and 0.00% of the galaxy convolved probability (Evans et al. 2016). Within T0 +/- 100 s, no significant detections (signal-to-noise ratio >~ 5 sigma) are found in the BAT raw light curves with time bins of 64 ms, 1 s, and 1.6 s. Assuming an on-axis (100% coded) short GRB with a typical spectrum in the BAT energy range (i.e., a simple power-law model with a power-law index of -1.32, Lien & Sakamoto et al. 2016), the 5-sigma upper limit in the 1-s binned light curve corresponds to a flux upper limit (15-350 keV) of ~ 7.12 x 10^-8 erg/s/cm^2. No event data are available at this point. BAT retains decreased, but significant, sensitivity to rate increases for gamma-ray events outside of its FOV. About 94.73% of the integrated LVC localization probability was outside of the BAT FOV but above the Earth's limb from Swift's location, and the corresponding flux upper limits for this region are within roughly an order of magnitude higher than those within the FOV. The results of the BAT analysis are available at https://swift.gsfc.nasa.gov/results/BATbursts/team_web/S190512at/web/source.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24519 SUBJECT: LIGO-Virgo S190512at: AGILE GRID observations DATE: 19/05/13 15:40:22 GMT FROM: Carlotta Pittori at ASI SSDC, INAF-OAR C. Pittori(SSDC, and INAF/OAR), A. Ursi(INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), C. Casentini, G. Piano, M. Cardillo (INAF/IAPS), F. Lucarelli, F. Verrecchia(SSDC, and INAF/OAR), A. Bulgarelli, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia(INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report on behalf of the AGILE Team: In response to the LIGO-Virgo GW event S190512at T0 = 2019-05-12 18:07:14.422 UTC (GCN #24503), analysis of AGILE data shows that the satellite at T0 was in the South Atlantic Anomaly (SAA). Scientific telemetry was inhibited during the time interval (T0 -13 s; T0 + 834 s). We performed a preliminary analysis of the AGILE Gamma-Ray Imaging Detector (GRID) in the first interval available after the SAA, between T0 +840s and T0+940s. In this time interval, due to Earth occultation and Solar Panel constraints, the GRID exposure covered only about 1% of the LIGO/Virgo 90% c.l. localization region (LR), observed at off-axis angles of about 60 deg. An analysis of the data in the energy range 50 MeV - 10 GeV in this integration time was performed, and preliminary 3-sigma upper limits (UL) values within the small accessible LIGO/Virgo localization region are: from 8.9e-7 erg cm^-2 s^-1 to 1.0e-6 erg cm^-2 s^-1 for an integration time of 100s. We also performed a search for a transient counterpart in the time window from T0 + 1 ks to T0 + 10 ks. In this time interval due to Solar Panel constraints, the GRID exposure covered about 40% of the LR, observed at off-axis angles from about 55 to 100 deg. Preliminary 3-sigma upper limits values are: from 2.8e-9 erg cm^-2 s^-1 to 1.0e-8 erg cm^-2 s^-1 for an integration time of 9 ks. An image of the AGILE-GRID exposure of S190512at in the time window from T0 + 1 ks to T0 + 10 ks is available at the site: https://tools.ssdc.asi.it/ImgView/Agile/AGILE_exp_T0p1k-T0p10k_S190512at9 These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24521 SUBJECT: LIGO/Virgo S190512at: Insight-HXMT/HE observation DATE: 19/05/13 16:44:01 GMT FROM: Qi Luo at IHEP Q. Luo, C. Cai, Q. B. Yi, S. Xiao, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: Insight-HXMT was taking data normally around the reported LIGO/Virgo S190512at event (GCN #24503), trigger time T0=2019-05-12 18:07:14 UTC. At T0, more than 95% of the LIGO localization region was covered by the Insight-HXMT without occultation by the Earth. Within T0 +/- 100 s, no significant excess events (SNR > 3 sigma) are found in a search of the Insight-HXMT/HE raw light curves. Assuming the GW counterpart GRB with three typical GRB Band spectral models, two typical duration timescales(1 s, 10 s) from the peak position of the LIGO-Virgo location probability map, the 5-sigma upper-limits fluence (0.2 - 5 MeV, incident energy) are reported below: Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV): 1s: 2.6e-07 erg cm^-2 10s: 7.4e-07 erg cm^-2 Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV): 1s: 3.6e-07 erg cm^-2 10s: 1.1e-06 erg cm^-2 Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV): 1s: 4.5e-07 erg cm^-2 10s: 1.9e-06 erg cm^-2 All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (record energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was fundedjointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information could be found at: http://www.hxmt.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24531 SUBJECT: LIGO/Virgo S190512at: CALET Observations DATE: 19/05/14 03:46:33 GMT FROM: Yuta Kawakubo at Louisiana State U./CALET A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The CALET Gamma-ray Burst Monitor (CGBM) was operating at the trigger time of S190512at T0=2019-05-12 18:07:14.422UT (The LIGO Scientific Collaboration and Virgo Collaboration, GCN Circ. 24503). No CGBM on-board trigger occurred around the event time. Based on the LIGO-Virgo localization sky map, most of the part of the high probability area was inside of the field-of-view of SGM. The summed LIGO probabilities inside the HXM and the SGM field of view are 19% and 95% (and 0% credible region of the initial localization map were Earth-occulted). The HXM and SGM field of views were centered at RA=205.5 deg, Dec = 44.8 deg and RA=214.9 deg, Dec=37.7 deg at T0. Based on the analysis of the light curve data with 0.125 sec time resolution from T0-60 sec to T0+60 sec, we found no significant excess around the trigger time in either the HXM (7-3000 keV) or the SGM (40 keV - 28 MeV) data. The CALET Calorimeter (CAL) was operating in high energy trigger mode at the trigger time of S190512at. Using CAL data, we have searched for gamma-ray events in the 10-100 GeV band from -60 sec to +60 sec from the GW trigger time and found no candidates. The 90% upper limit of CAL is 1.9x10^-5 erg/cm2/s (10-100 GeV) when the summed LIGO-Virgo probability reaches 10%. The CAL FOV was centered at RA=214.9 deg, Dec=37.7 deg at T0. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24584 SUBJECT: LIGO/Virgo S190512at: Updated sky localization DATE: 19/05/17 17:42:03 GMT FROM: Deep Chatterjee at University of Wisconsin, Milwaukee The LIGO Scientific Collaboration and the Virgo Collaboration report: We have re-analyzed LIGO and Virgo data around the time of the compact binary coalescence (CBC) candidate S190512at (GCN 24503). Parameter estimation has been performed using LALInference [1] and a new sky map, LALInference.fits.gz, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S190512at The preferred skymap at this time is LALInference.fits.gz. For the LALInference.fits.gz skymap, the 90% credible region is 252 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1388 +/- 322 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo Public Alerts User Guide . [1] Veitch et al. PRD 91, 042003 (2015) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24615 SUBJECT: LIGO/Virgo S190512at: SVOM/GWAC-F60A observations DATE: 19/05/20 22:38:43 GMT FROM: Xiang-Gao Wang at GuangXi U X.G. Wang (GXU), X.H. Han (NAOC), L.P. Xin (NAOC), J.Y. Wei (NAOC), C. Wu (NAOC), D. Turpin (NAOC), N. LEROY (CNRS/LAL), S. ANTIER (CNRS/APC/CNES), L. Huang (NAOC), Y. Xu (NAOC), H.B. Cai (NAOC), J. Wang (NAOC), X.M. Lu (NAOC), Y.L. Qiu (NAOC), J.S. Deng (NAOC), L. Jia (NAOC), S.C. Zou (NAOC), S.F. Liu (NAOC), Q.C. Feng (NAOC), H.L. Li (NAOC), D.W. Xu (NAOC), Y.J. Xiao (NAOC), W.L. Dong (NAOC), Y.T. Zheng (NAOC), P. P. Zhang (NAOC), R.S. Zhang (NAOC), E.W. Liang (GXU), Z.G. Dai (NJU), X.Y. Wang (NJU), Y.G. Yang (HBNU), J.R. Mao (YNAO), B. Cordier (CEA/AIM), S. Basa (CNRS/LAM), J.L. Atteia (UPS/IRAP),D. Gotz (CEA/AIM), A. Claret (CEA/AIM), C. Lachaud (CNRS/APC), R. Duque (CNRS/IAP), N. Dagoneau (CEA/AIM) S.N. Zhang (IHEP), B.B. Wu (IHEP), report on behalf of the SVOM Ground Follow-up Group: We observed the LIGO/Virgo trigger S190512at (GCN #24503) with GWAC-F60A. Two 60cm GWAC-F60(A/B) are operated by Guangxi University and NAOC, CAS, at Xinglong Observatory. China. They are equipped with Standard Johnson filters and 2Kx2K Andor CCD (FOV~18x18 arcmin). GWAC-F60(A/B) are used for galaxy-targeted observations. The galaxies are selected from the GLADE catalog (Version 2.3, Dalya et al. 2018) in the probability skymap of GW event. All these galaxies were observed in clear band. The first image was taken ~19.7 hours after the event trigger time T0=2019-05-12 18:07:14 UTC. No credible new source was detected in our pipeline. A total number of 43 galaxies were observed. The coordinates (J2000) of galaxies, the observation time, the limit magnitude (3sigma) and telescopes are listed below: No. RA DEC Start-obs(UTC) Limit (R) Telescope 1 14:36:42.001 +09:55:45.26 2019-05-13T12:48:33.079 19.59 F60A 2 14:38:47.519 +10:07:17.04 2019-05-13T13:59:47.864 18.46 F60A 3 15:06:45.119 -01:13:54.23 2019-05-13T12:58:55.753 19.10 F60A 4 14:44:29.281 +04:44:40.85 2019-05-13T12:37:01.477 19.24 F60A 5 15:11:41.039 -03:53:54.74 2019-05-13T15:18:18.559 19.27 F60A 6 14:41:26.880 +09:15:27.54 2019-05-13T19:34:49.642 18.24 F60A 7 14:33:06.001 +09:40:09.84 2019-05-13T12:42:46.387 19.24 F60A 8 14:52:11.521 +02:18:38.34 2019-05-13T17:38:24.972 19.25 F60A 9 14:47:03.599 +05:35:25.04 2019-05-13T14:06:27.778 19.76 F60A 10 14:41:04.081 +07:42:45.22 2019-05-13T15:52:57.033 19.37 F60A 11 14:34:30.241 +10:52:33.96 2019-05-13T16:22:25.302 19.01 F60A 12 14:59:57.599 -01:27:03.74 2019-05-13T14:41:19.946 19.76 F60A 13 15:09:39.121 -03:10:39.29 2019-05-13T13:04:32.492 18.76 F60A 14 15:17:08.401 -07:34:10.88 2019-05-13T16:27:42.187 18.91 F60A 15 15:10:43.680 -04:56:05.24 2019-05-13T18:20:32.299 19.40 F60A 16 15:05:41.039 -04:53:12.30 2019-05-13T14:23:45.297 19.54 F60A 17 15:07:06.960 -04:31:52.07 2019-05-13T14:12:11.179 19.36 F60A 18 14:59:18.960 +00:44:08.88 2019-05-13T15:30:56.668 19.28 F60A 19 14:41:17.279 +07:47:49.56 2019-05-13T19:12:41.070 19.03 F60A 20 14:43:29.521 +07:54:22.00 2019-05-13T18:29:10.610 19.43 F60A 21 14:36:18.479 +10:36:02.16 2019-05-13T14:35:29.636 19.70 F60A 22 14:45:29.761 +07:48:44.10 2019-05-13T18:43:34.454 19.87 F60A 23 15:05:42.961 -03:49:32.30 2019-05-13T18:07:18.669 19.34 F60A 24 15:20:03.599 -07:42:09.43 2019-05-13T14:29:34.082 19.04 F60A 25 15:24:07.920 -08:08:10.64 2019-05-13T14:17:57.171 19.00 F60A 26 15:29:28.799 -11:21:48.96 2019-05-13T15:24:50.133 19.28 F60A 27 14:38:47.519 +10:07:17.04 2019-05-13T13:59:47.864 18.46 F60A 28 15:11:41.039 -03:53:54.74 2019-05-13T15:18:18.559 19.27 F60A 29 14:41:26.880 +09:15:27.54 2019-05-13T19:34:49.642 18.24 F60A 30 14:52:11.521 +02:18:38.34 2019-05-13T17:38:24.972 19.25 F60A 31 14:47:03.599 +05:35:25.04 2019-05-13T14:06:27.778 19.76 F60A 32 14:41:04.081 +07:42:45.22 2019-05-13T15:52:57.033 19.37 F60A 33 14:34:30.241 +10:52:33.96 2019-05-13T16:22:25.302 19.01 F60A 34 14:59:57.599 -01:27:03.74 2019-05-13T14:41:19.946 19.76 F60A 35 15:17:08.401 -07:34:10.88 2019-05-13T16:27:42.187 18.91 F60A 36 15:10:43.680 -04:56:05.24 2019-05-13T18:20:32.299 19.40 F60A 37 15:05:41.039 -04:53:12.30 2019-05-13T14:23:45.297 19.54 F60A 38 15:07:06.960 -04:31:52.07 2019-05-13T14:12:11.179 19.36 F60A 39 14:59:18.960 +00:44:08.88 2019-05-13T15:30:56.668 19.28 F60A 40 14:41:17.279 +07:47:49.56 2019-05-13T19:12:41.070 19.03 F60A 41 14:43:29.521 +07:54:22.00 2019-05-13T18:29:10.610 19.43 F60A 42 14:36:18.479 +10:36:02.16 2019-05-13T14:35:29.636 19.70 F60A 43 14:45:29.761 +07:48:44.10 2019-05-13T18:43:34.454 19.87 F60A This circular is citable.